docs: update changelog.

docs/changelog.rst

@@ -146,11 +146,11 @@ Core Library
   was fixed.
 
 * `#337 <https://github.com/dw/mitogen/issues/337>`_: to avoid a scaling
-  limitation, SSH no longer allocates a PTY for every OpenSSH client. PTYs are
+  limitation, SSH now longer allocates a PTY for every OpenSSH client if it can
-  only allocated if a password is supplied, or when `host_key_checking=accept`.
+  be avoided. PTYs are only allocated if a password is supplied, or when
-  This is since Linux has a default of 4096 PTYs (``kernel.pty.max``), while OS
+  `host_key_checking=accept`. This is since Linux has a default of 4096 PTYs
-  X has a default of 127 and an absolute maximum of 999
+  (``kernel.pty.max``), while OS X has a default of 127 and an absolute maximum
-  (``kern.tty.ptmx_max``).
+  of 999 (``kern.tty.ptmx_max``).
 
 * `#339 <https://github.com/dw/mitogen/issues/339>`_: the LXD connection method
   was erroneously executing LXC Classic commands.